twisting groundwires
- Thread starter tdjs
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highkvoltage
Senior Member
Re: twisting groundwires
Nothing.
Nothing.
- Location
- Bremerton, Washington
Re: twisting groundwires
It was common some time ago to twist the EGC togehter and then terminate under one lug.
Its not done much anymore and actually would be more of a disadvantage.
It was common some time ago to twist the EGC togehter and then terminate under one lug.
Its not done much anymore and actually would be more of a disadvantage.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: twisting groundwires
He may be referring to the practice of twisting together ground wires but not securing them together with a wire nut. I have opened up a couple of outlet boxes in my own home and found this.
I guess the electrician could not afford enough wire nuts.
He may be referring to the practice of twisting together ground wires but not securing them together with a wire nut. I have opened up a couple of outlet boxes in my own home and found this.
I guess the electrician could not afford enough wire nuts.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: twisting groundwires
Oh, I think he's asking about is it necessary to twist according to code, or does the wire nut do the job?
Code is silent on that. Code is also quiet on how to tie a three-way, but we do it everyday.
I twist. I don't understand why you feel it to be a disadvantage, Tom? My boxes would be unmanageable from a neatness standpoint if I didn't twist the grounds together.
Oh, I think he's asking about is it necessary to twist according to code, or does the wire nut do the job?
Code is silent on that. Code is also quiet on how to tie a three-way, but we do it everyday.
I twist. I don't understand why you feel it to be a disadvantage, Tom? My boxes would be unmanageable from a neatness standpoint if I didn't twist the grounds together.
Ed MacLaren
Senior Member
Re: twisting groundwires
Recently, while installing a generator transfer switch, I had to move some cables from the main panel to the generator panel.
The electrician had twisted the EGCs together before connecting them to the ground bar in the panel.
I'm afraid I said some *#@+%$!* words.
Ed
Recently, while installing a generator transfer switch, I had to move some cables from the main panel to the generator panel.
The electrician had twisted the EGCs together before connecting them to the ground bar in the panel.
I'm afraid I said some *#@+%$!* words.
Ed
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: twisting groundwires
The code is not silent on spices.
The code is not silent on spices.
As far as the twisting, read the manufacturers instructions for the "wire nuts". Some allow it and some don't.
peter d
Senior Member
- Location
- New England
Re: twisting groundwires
250.148 is an important code article on this subject, yet is widely ignored. Many electricians dangerously assume that since the grounding conductor is not normally current carrying, it does need menchanical connection.
Mechanical connections such as wire connectors and crimp lugs are required.
Simply twisting the grounding conductors together is not adequate, and in fact, could create a high impedance connection under fault conditions. Many fires have ignited this way.
250.148 is an important code article on this subject, yet is widely ignored. Many electricians dangerously assume that since the grounding conductor is not normally current carrying, it does need menchanical connection.
Mechanical connections such as wire connectors and crimp lugs are required.
Simply twisting the grounding conductors together is not adequate, and in fact, could create a high impedance connection under fault conditions. Many fires have ignited this way.
- Location
- Illinois
- Occupation
- retired electrician
Re: twisting groundwires
Dave,
Don
Dave,
Are you sure that some don't permit pretwisting? Can you cite a source? The only ones that I have ever seen said "pretwisting not necessary". That is not the same as saying "don't pretwist".
Don
physis
Senior Member
Re: twisting groundwires
I was working on a building recently where the grounding conducter of the NM's were just twisted together, rather loosely too. My faith in that conducter clearing a fault is just the tiniest bit more than zero.
I can sort of deduce the installing electricians state of mind on the subject because in some boxes the grounding conducter was simply clipped off. Since it doesn't do anything anyway?
I was working on a building recently where the grounding conducter of the NM's were just twisted together, rather loosely too. My faith in that conducter clearing a fault is just the tiniest bit more than zero.
I can sort of deduce the installing electricians state of mind on the subject because in some boxes the grounding conducter was simply clipped off. Since it doesn't do anything anyway?
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: twisting groundwires
Don,
You're right, "pretwisting not necessary".
Don,
You're right, "pretwisting not necessary".
B
bthielen
Guest
Re: twisting groundwires
I understand how troublesome it is to have to untwist the grounds to remove a wire but how do you manage stuffing all the wires into the device box while still being sure the bare grounds don't contact hot or neutral terminals on the devices? I picture a gang box with a half-dozen ground wires along with the bare pigtails being stuffed back into the box as one is fastening a couple duplex receptacles in place. It's bad enough being sure the twisted ones are controlled much less a bunch of spagetti. Seems like a potential short-circuit in the making.
Bob
I understand how troublesome it is to have to untwist the grounds to remove a wire but how do you manage stuffing all the wires into the device box while still being sure the bare grounds don't contact hot or neutral terminals on the devices? I picture a gang box with a half-dozen ground wires along with the bare pigtails being stuffed back into the box as one is fastening a couple duplex receptacles in place. It's bad enough being sure the twisted ones are controlled much less a bunch of spagetti. Seems like a potential short-circuit in the making.
Bob
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: twisting groundwires
I love how some guys won't go so far as to clip them off, but leave them too stinkin' short to do anything with in the future. A tad bit more wire goes a long way if you're going to eliminate or add a cable to the box someday. Somehow the 6" rule doesn't seem to apply to the ground in some minds.
I love how some guys won't go so far as to clip them off, but leave them too stinkin' short to do anything with in the future. A tad bit more wire goes a long way if you're going to eliminate or add a cable to the box someday. Somehow the 6" rule doesn't seem to apply to the ground in some minds.
peter d
Senior Member
- Location
- New England
Re: twisting groundwires
It's one thing inspectors never seem to catch in my area, probably because they don't know any better themselves. :roll:
I agree George. That's one of my pet peeves.Originally posted by georgestolz:
Somehow the 6" rule doesn't seem to apply to the ground in some minds.
It's one thing inspectors never seem to catch in my area, probably because they don't know any better themselves. :roll:
Re: twisting groundwires
--
Tom Horne
I don't have my code here so I may not get this right but I thought the code required the free conductor length at the box to permit make up. That would mean that the length need not be that long after make up. In other words I would think that you could only inspect for the required free conductor length at rough in inspection but not on later inspection after the splices and terminations are made up. That does not mean that I think shortening them up is good practice I'm just not sure that it is a code violation.Originally posted by georgestolz:
I love how some guys won't go so far as to clip them off, but leave them too stinkin' short to do anything with in the future. A tad bit more wire goes a long way if you're going to eliminate or add a cable to the box someday. Somehow the 6" rule doesn't seem to apply to the ground in some minds.
--
Tom Horne
peter d
Senior Member
- Location
- New England
Re: twisting groundwires
Tom,
The wording of 300.14 gives no "wiggle room" on the 6" rule.
The conductors must be 6" long, and they must extend past the face of the box 3" if the box is less than 8" in any dimension.
Tom,
The wording of 300.14 gives no "wiggle room" on the 6" rule.
The conductors must be 6" long, and they must extend past the face of the box 3" if the box is less than 8" in any dimension.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: twisting groundwires
I've seen spec's on plans that required an additional 3" over code on all conductors to permit device replacement three times in the future. That practice left an impression on me, now I leave them at least that long in every box.
I've seen spec's on plans that required an additional 3" over code on all conductors to permit device replacement three times in the future. That practice left an impression on me, now I leave them at least that long in every box.
pierre
Senior Member
- Location
- Westchester County, New York
Re: twisting groundwires
300.14
"At least (6in.) of free conductor, measured from the point in the box where it emerges from its raceway or CABLE SHEATH," ...
If one were to run the sheath into the box say an inch, technically you would need 7 inches of conductor/cable.
300.14
"At least (6in.) of free conductor, measured from the point in the box where it emerges from its raceway or CABLE SHEATH," ...
If one were to run the sheath into the box say an inch, technically you would need 7 inches of conductor/cable.
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